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| Waste water purification |
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| Wastewater treatment process |
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| Anaerobic filter |
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Method of producing permeable, porous molded bodies of silicon carbide
| Details |
Inventors: Dias, Francisco J.; Kampel, Marian; Luhleich, Hartmut;
Assignee: Kernforschungsalage Julich GmbH (Julich, DE)
Primary Examiner:
Assistant Examiner:
Attorney, Agent or Firm:
A porous green-state body of carbon, with or without silicon carbide, made with a cokable binder, is crumbled to produce relatively coarse grains in the range from 0.2 to 10 mm and a fraction of the particles so produced with a much more limited range of grain size is then used to produce a second green-state body, which is then coked, siliconized if the silicon is not already provided in the making of the precursor body that was broken up, and converted into a silicon carbide body. If the siliconizing is done by immersion in a bath of molten silicon, the excess silicon is removed by vaporization or by boiling in sodium hydroxide solution. |
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DETAILED DESCRIPTION We claim: 1.
Method of producing permeable porous molded bodies of silicon carbide, comprising the steps of: molding a green-state precursor body from a composite powder made of carbon particles, silicon particles, from 0 to 70% by weight of silicon carbide particles, and a cokable organic binder; breaking up said precursor body into a coarse granulate of a principal grain size in the range from 0.
2 to 10 mm; obtaining from said granulate a fraction thereof of limited size range, said limited size range not exceeding a 2:1 ratio between the largest and smallest granules; molding a second green-state body from said granulate fraction, with application of pressure which is selected from relatively light to heavy to produce the desired permeability of the silicon carbide body; coking said organic binder by heating said second green-state body up to a temperature in the range between 600.
degree.
and 1000.
degree.
C.
in vacuum or in an inert atmosphere, and converting the carbon and silicon of said body into silicon carbide by rapidly heating up said body, after the coking of said organic binder, to a temperature between 1400.
degree.
and 1900.
degree.
C.
in an inert atmosphere.
2.
Method of producing permeable porous molded bodies of silicon carbide, comprising the steps of: molding a green-state precursor body from a composite powder made of carbon particles, from 0 to 70% by weight of silicon carbide particles and a cokable organic binder; breaking up said precursor body into a coarse granulate of a principal grain size in the range from 0.
2 to 10 mm; obtaining from said granulate a fraction thereof of limited size range, said limited size range not exceeding a 2:1 ratio between the largest and smallest granules; molding a second green-state body from said granulate fraction, with application of pressure which is selected from relatively light to heavy to produce the desired permeability of the silicon carbide body; coking said organic binder by heating said second green-state body up to a temperature in the range between 600
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Liquid Purification 
